Cecilia's Lightning Fastball

You weave a ball of lightning and hurl it at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d8 lightning damage. When you roll a 20 on the attack roll, roll all of the attack's damage dice three times and add them together.

This spell's damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).